It is known that moisture can intrude into the wall space of a building, for example between the external cladding and internal lining of a house, and cause significant damage. It is an object of a preferred form of the present invention to provide means suitable for use in detecting unacceptable levels of moisture within a wall space, or to provide the public with a useful choice.
The term “comprising” or derivatives thereof (eg “comprises”), if and when used herein, should be interpreted non-exclusively—eg if used in relation to a specific combination of features it should not be taken to exclude the possibility of there also being additional unspecified features.